Method for producing a partitioned bottle

ABSTRACT

A method for producing a partitioned container of the present invention includes the steps of providing a preform having an interior surface; separately forming an inner wall for insertion into the preform; inserting the inner wall into the preform; preparing for molding and molding the preform and inner wall into the partitioned container; and activating a manner for securing the inner wall to the interior surface of the preform during the step of preparing. A system for forming a partitioned container in accordance with the present invention includes a preform including an interior surface surrounding a cavity; an inner wall formed separately from the preform, the inner wall including a manner for securing to the preform upon the application of heat thereto, and a molding device for molding the preform into the container. During preparation for molding of the preform into the container, the preform and inner wall are heated and the manner for securing is activated, thereby securing the inner wall to the interior surface.

BACKGROUND OF THE INVENTION

This invention is directed to a process for molding containers, and moreparticularly, to an improved process for molding partitioned containersfrom a preform and a separately formed inner wall, wherein the innerwall is secured to the preform prior to molding the container.

Partitioned containers and methods for making the same are well known inthe art. In most cases, a preform is used to form the partitionedcontainer, which preform has integrally formed therewith the requiredpartitions or walls and the like for forming the partitions of thefinished container. That is, typically a complex mold is required toinjection mold or otherwise form a preform having integral partitionsextending across the cavity thereof. Alternatively, a simple preform maybe formed having a hollow cavity and a separately formed partitionsubsequently secured therein. In these cases, securing the partition tothe inside surface of the preform is problematic in that the partitionmust be caused to maintain its engagement with the inside surface of thepreform during subsequent blow molding operations for forming thecontainer. In addition to withstanding expansion during molding and itssecurement with the inner surface of the preform, the partition mustalso reliably maintain its engagement with the inner wall of thecontainer after the container is formed. Still another method of forminga partitioned container is to injection mold the entire container of oneconstruction including the partitions. Typically, multiple fairly largeand complex injection molds are required for this method.

The prior art includes a plurality of partitioned containers, none ofwhich cure the problems in forming partitioned containers, as set forthabove.

U.S. Pat. No. 5,398,828 to Valyi discloses a blow molded plasticcontainer including an internal support and handgrips. The blow moldedcontainer includes at least one internal supporting member integral withthe inside wall of the body portion to support the same. The bodyportion defines lobes connected together by depressions which define ahandgrip. The depressions are supported by the internal supportingmember. The internal supporting member is formed integral with thepreform during molding thereof and is then blow molded into the internalmember of the container.

U.S. Pat. No. 5,135,823 to Eales discloses a modular multi-compartmentedblow molded container. The container includes partition members forforming the compartments therein which initially form portions of a moldfor the container. When molding is complete, the partition members formpart of the container, with the molded plastic material of the containersubstantially surrounding the partition members. In another embodiment,the containers are modular, wherein mating engagement members are formedin facing walls of separate container portions that are joinedsubsequent to molding. The container portions can be made detachable orpermanently attached. Accordingly, in this container, the partitions areprovided during molding of the container, wherein the partitions are apart of the mold which are adapted to become a part of the container.

U.S. Pat. No. 5,232,108 to Nakamura discloses a preform having an innerpartition wall and a process for making a plastic vessel therefromhaving an inner partition wall. The preform has an internal partitionwall formed to extend across the interior of the barrel portion of thepreform and up from the bottom portion thereof. The internal partitionwall is injection molded along with the remaining portion of the preformduring the formation thereof. The same wall is later blow molded intothe partition for the container.

U.S. Pat. No. 4,277,000 to Jaarsma discloses multi-compartmentedcontainers. The multi-compartmented containers include a molded body anda molded cap secured thereto. The body includes a confining wall forminga space, an internal dividing wall forming separate compartments withinthe space and a base. A fluid seal is formed by the confining wall andthe inside surface of the body of the container. The entire container isformed from injection molding, including the formation of the dividingwall.

U.S. Pat. No. 4,065,536 to Lucus discloses a method of making aprecisely partitioned bulbous-shape container. The container is formedfrom a preform having a partition integrally formed therein during theformation of the preform. Accordingly, the partition is integral to theremaining body portion of the preform.

PCT Application GB89/01362 discloses a partitioned plastic container.The container is formed from an injection molded preform, wherein thepreform has an integrally formed partition therein which is also formedduring the injection molding process. The preform and partition arelater blown into the shape of a container having a partition therein.

There exists a need, therefore, for an improved process for forming apartitioned container which process allows for the use of a simplepreform and provides a reliable manner for attaching a separately formedpartition thereto and to sustain the attachment during formation of thecontainer to be formed thereby and to the container after formation.

SUMMARY OF THE INVENTION

The primary object of this invention is to provide an improved methodfor forming partitioned containers.

Another object of this invention is to provide a method for formingpartitioned containers, wherein the partitioned container is formed froma preform which includes a separately formed inner wall reliably securedtherein.

Still another object of this invention is to provide an improved methodfor forming a partitioned container, which container is formed from apreform including a separately formed inner wall and which inner wall issecurely bonded to the interior surfaces of the preform and containervia a heat activated adhesive which is activated before and/or duringthe molding preparation and molding of the preform.

The foregoing objects and following advantages are achieved by themethod for producing a partitioned container of the present inventionwhich comprises the steps of providing a preform having an interiorsurface; separately forming an inner wall for insertion into thepreform; inserting the inner wall into the preform; preparing formolding and molding the preform and inner wall into the partitionedcontainer; and activating a manner for securing the inner wall to theinterior surface of the preform during the step of preparing.

The objects and advantages are also achieved by a system for forming apartitioned container in accordance with the present invention whichcomprises a preform including an interior surface defining a cavity; aninner wall formed separately from the preform, the inner wall includingmeans for securing to the preform upon the application of heat thereto,and means for molding the preform into the container. During preparationfor molding into the container via the means for molding, the preformand inner wall are heated and the means for securing is activated,thereby securing the inner wall to the interior surface.

The details of the present invention are set out in the followingdescription and drawings wherein like reference characters depict likeelements.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a process for forming a partitionedcontainer in accordance with the principles of the present invention;

FIG. 2 is an elevational view of a preform used in accordance with theprinciples of the present invention in the method shown in FIG. 1;

FIG. 3 is a perspective view of an inner wall used in the preform shownin FIG. 2 for the method of FIG. 1;

FIG. 4 is an enlarged cross-sectional view taken along line 4--4 in FIG.2;

FIG. 5 is a perspective view of an example of a container formed inaccordance with the method of the present invention; and

FIG. 6 is a cross-sectional view similar to that shown in FIG. 4 butdisclosing an alternative embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings in detail, there is shown in FIG. 1 aschematic view of a process for forming a compartmented container, whichprocess is designated generally as 10. The process generally includesstep 12, molding or providing a preform; step 14, separately forming aninner wall for insertion into the preform; step 16, inserting the innerwall into the cavity of the preform; step 18, preparing the preform formolding and activating a manner for securing the inner wall to theinterior surface of the preform; and step 20, molding the preform andinner wall into a partitioned container. These process steps arediscussed in further detail below.

In step 12, and referring to FIG. 2, a preform 21 is formed inaccordance with known methods, i.e. preferably injection molded to havea well known shape including a body portion 22 and a threaded and/orflange portion 24, which portions 22 and 24 define a cavity 26surrounded by an interior surface 28. As shown in both FIGS. 2 and 4,interior surface 28 is formed with slots 30a and 30b extendinglongitudinally therein for receiving inner wall 32.

In step 14, and referring to FIGS. 3 and 4, inner wall 32 is formedseparately from preform 21 in a size to fit into cavity 26 of preform21. Preferably inner wall 32 is longitudinal and rectangular in shapehaving contact edges 34a and 34b for insertion into slots 30a and 30b,respectively, and includes faces 35a and 35b. As shown in FIGS. 2-4,inner wall 32 is sized to fit into cavity 26 of preform 21, and extendacross cavity 26, thereby forming two compartments 36 and 38.

In step 16, inner wall 32 is inserted into cavity 26 of preform 21, inslots 30a and 30b, as shown in FIG. 4.

In step 18, preform 21 is prepared for blow molding by heating andaccordingly, inner wall 32 is secured to the interior surface 28 ofpreform 21 in slots 30. This step is preferably accomplished by using aheating element (not shown) and a heat activated adhesive 39 which iscoated onto inner wall 32, as shown in FIG. 4, preferably on edges 34aand 34b and preferably on at least a portion of faces 35a and 35b in theareas 40a and 40b, immediately adjacent edges 34a and 34b. Adhesive 39may also extend over the entirety of faces 35a and 35b.

Therefore, as the preform is heated for blow molding in step 18,adhesive 39 is activated and thereby secures inner wall 32 at edges 34aand 34b and longitudinal areas 40a and 40b to the walls of slots 30a and30b formed in preform 21. Once the inner wall is securely held to theinterior surface 28 of preform 21, the actual step of blow molding, step20, is performed, thereby stretching the inner wall 32 across the entirediameter of the container being formed.

Accordingly, adhesive 39 is adapted to have a temperature activationrange which is effectively activated in the blow molding preparationtemperature range. By activation, the adhesives may become tacky,melted, or chemically activated to cause adherence to interior surface28 of preform 21. A number of adhesives having these properties areknown in the art and accordingly, any such adhesives may be used withsuccess, and the particular one chosen may be dictated by thepreparation requirements of the molding material chosen. For someadhesives completed activation and reliable adherence may occur duringthe actual molding step.

In step 20, preform 21 is molded into partitioned container 41, shown inFIG. 5, preferably using a blow molding technique well known in the art.During blow molding or the like and in the scenario where PET(Polyethylene Terephthalate) is used, the temperature reached formolding is typically 95°-110° C., in which range, the chosen adhesive 39is preferably activated.

Accordingly, container 41 shown in FIG. 5 is thereby formed having aninner wall reliably secured therein. Preferably, although not required,the inner wall is of a length such that it does not extend the entirelength of the body portion of container 41, as shown, allowing for fluidflow underneath the inner wall. Alternatively, if desired, the innerwall may extend the entire length of the container from the base to theneck to form separate, self-contained compartments. The inner wall maybe used, for example, for playing games or for displaying things such asadvertisements and the like, or for supporting an integral handgrip, orfor forming separate compartments.

Referring again to step 18 and now FIG. 6, an alternative embodiment ofinner wall 32 for increasing the strength of the bond between inner wall32 and interior surface 28 of preform 21, is shown. In this embodiment,the ends of inner wall 32 are formed into hook-like members 42a and 42b,the outer surfaces of which include edges 34a and 34b. By forming thelongitudinally extending ends of inner wall 32 into hook-like members42a and 42b, increased surface areas 44a and 44b, defined by the outersurface of the hook-like members and including edges 34a and 34b, areobtained for improved securement to the surfaces of slots 30a and 30b.In this embodiment, adhesive 39 is preferably spread over the entireouter surfaces 44a and 44b of the hook-like members 42a and 42b and thehook-like members 42a and 42b are preferably of a size to snugly fitinto slots 30a and 30b, respectively. Accordingly, when adhesive 39 isactivated during heating during blow molding preparation and/or duringmolding, the entirety of outer surfaces 44a and 44b of hook-like members42a and 42b are caused to adhere to the surfaces of slots 30a and 30b,respectively, thereby obtaining a stronger connection between inner wall32 and interior surface 28 of preform 21.

While an inner wall has been shown herein having only two faces forforming only two compartments, it is to be understood that variouslyshaped inner walls, such as those having more than two faces, may beused so as to form any number of compartments in container 41. That is,an inner wall having a cross-section resembling the interior of a peacesign or a plus sign may also be used with the method described hereinfor forming containers having three or four compartments, respectively.A variety of other shapes for forming even more compartments may also beused. For these embodiments, the same slot and adhesive arrangements maybe used for achieving a secure bond between the inner wall and thepreform and the inner wall and the container.

The primary advantage of this invention is that an improved method isprovided for forming partitioned containers. Another advantage of thisinvention is that a method is provided for forming partitionedcontainers, wherein the partitioned container is formed from a preformwhich includes a separately formed inner wall reliably secured therein.Still another advantage of this invention is that an improved method isprovided for forming a partitioned container, which container is formedfrom a preform including a separately formed inner wall and which innerwall is securely bonded to the interior surfaces of the preform andcontainer via a heat activated adhesive which is activated before and/orduring the molding of the preform into the container.

It is to be understood that the invention is not limited to theillustrations described and shown herein, which are deemed to be merelyillustrative of the best modes of carrying out the invention, and whichare susceptible of modification of form, size, arrangement of parts anddetails of operation. The invention rather is intended to encompass allsuch modifications which are within its spirit and scope as defined bythe claims.

What is claimed is:
 1. A method for producing a partitioned container,comprising the steps of:providing a preform having a closed bottom, sidewalls, an open end and an interior surface; separately forming an innerpartition wall for insertion into said preform, said inner wall havingcontact edges for engagement with said interior surface; inserting saidinner wall into said preform with means for securing said contact edgesto said interior surface provided between said contact edges andinterior surface, and securing said contact edges to said interiorsurface by said means for securing, to form an internal, longitudinallyextending partition in said preform; molding said preform and inner wallinto said partitioned container, with said partitioned container havingan inside diameter; wherein said interior surface includes slots forengagement with said contact edges; and wherein said molding comprisesblow molding said preform including stretching the inner wall across theinside diameter of the container.
 2. The method according to claim 1,wherein said inner wall has a length and said slots extends asubstantial portion of said length.
 3. The method according to claim 1,including the step of heating said preform to secure the contact edgeswith said interior surface.
 4. The method according to claim 3, whereinsaid means for securing comprises a heat activated adhesive, includingthe step of activating said heat activated adhesive during said step ofheating for securing said inner wall to said interior surface.
 5. Themethod according to claim 1, wherein said contact edges are curled forfacilitating increased engagement with said interior surface.
 6. Themethod according to claim 1, wherein said inner wall is an elongatedsubstantially planar inner wall adapted to extend across the diameter ofsaid preform.
 7. The method according to claim 1, wherein said step ofinserting includes the step of sliding said inner wall into said slotsformed in said interior surface.
 8. The method according to claim 1,wherein said step of providing comprises injection molding said preform.9. The method according to claim 8, wherein said means for securingcomprises a heat activated adhesive and including activating said meansfor securing by said heat activated adhesive becoming at least one oftacky, melted, or chemically activated to facilitate securing.
 10. Themethod according to claim 1, including the step of forming the innerpartition wall without openings thereon.
 11. The method according toclaim 10, wherein the partitioned container defines separate,self-contained compartments.